Rhabdomyolyse massive révélant une maladie de McArdle

Cardiac arrest as a manifestation of unknown Type V glycogenosis: a case report

Few cases have been reported to date, in which a massive rhabdomyolysis causes a cardiac arrest in a male adult suffering from undiagnosed McArdle disease. Veno-arterial extracorporeal membrane oxygenation and cytokine adsorption filter (CytoSorb®) were required to reach a complete and successful recovery.

Novel Asp511Thr mutation in McArdle disease with acute kidney injury caused by rhabdomyolysis

McArdle disease (glycogen storage disease type V) is a rare hereditary metabolic myopathy. It can be overlooked clinically because it often presents as chronic asymptomatic hypercreatine phosphokinasemia (hyperCKemia). However, vigorous exercise or infections can trigger severe rhabdomyolysis. We present the case of a patient with long-term idiopathic hyperCKemia who, after contracting an upper respiratory tract infection, developed severe rhabdomyolysis and acute kidney injury. Upon hemodialysis, his renal function recovered and CK levels fell to below baseline, and maintenance therapy with vitamin B6 was also started. A molecular diagnosis of McArdle disease was subsequently made. Whole-exome sequencing revealed homozygous c1538delG (p.Asp511Thr fs*28) mutations in the PYGM gene, which was a novel mutation. Therefore, when investigating idiopathic hyperCKemia, glycogen storage disorders should also be considered.

[McArdle disease revealed by exercise intolerance associated with severe rhabdomyolysis]

McArdle's disease (MAD) is a rare hereditary myopathy secondary to a deficit in myophosphorylase, an essential enzyme for the use of muscular glycogen reserves. Exercise intolerance to a variable degree is the fundamental manifestation. Muscular enzymes are usually normal or slightly elevated, except during episodes of rhabdomyolysis. Generally, the electromyogram has poor sensitivity for the diagnosis of exercise myopathies. The muscular biopsy can be misleadingly normal. The role of MRI in the diagnosis of MAD is not well clarified in the literature. We report the case of a 16-year-old patient, hospitalized in July 2008 for exercise intolerance. On admission, he was asymptomatic and the physical examination was non contributive. Serum creatine kinase levels and renal function measures were normal. Cycloergometer exercise testing unmasked the disease. EMG and muscular biopsies were normal. During the second hospitalization, this time for rhabdomyolysis, T2 weighted MRI of the thighs showed high intensity signals from the gracilis muscles. The control MRI, made after 2 weeks of rest, was normal. Right gracilis muscle biopsy demonstrated excess glycogen with myophosphorylase deficiency, establishing the diagnosis of MAD. MAD is a rare metabolic myopathy to consider in patients with a history of exercise intolerance. The muscle biopsy can be misleadingly normal and should be, to our opinion, be guided by MRI findings.

[Spurious inclusion body myositis: repeat the muscle biopsy]

Inclusion body myositis, although rare, is the commonest cause of myopathy in patients aged over 55 years. We report a 62-year-old man presenting a glycogen storage disease type 2 mimicking an inclusion body myositis.